In order to set the watch to another time zone, the wearer simply needs to push down the bezel, turn it to the desired time zone and let it go – the hour hand, 24-hour day/night display and the date automatically move with the bezel. The time zones that have daylight saving time are marked with a small “S” on the rotating bezel. To create the mechanism required for this complication, IWC’s engineers brought together three technologies. The first of these is the city ring found on the Pilot’s Watch Worldtimer, on which the name of each city stands for one of the international time zones. The second technology is the spring-mounted rotating bezel, first used in the Porsche Design Ocean 2000 from the 1980s, which can only be moved if pressure is applied simultaneously on two diametrically opposing sides. This prevents accidental resetting of the time zone. The third technology is the external/internal rotating bezel taken from the Aquatimer, which transmits the movement of the bezel via a differential gear to the hour wheel, 24-hour hand and date advance wheel.